Various types of position sensors have been used to determine the rotational, linear, and planar positions of a movable device. Some applications require a certain level of redundancy or dependability; in such cases, multiple position sensors can be used to detect a single position coordinate for the movable device.
For example, in an application where a device moves in two dimensions, multiple x-axis sensors could be used to redundantly determine the device's x-axis position and multiple y-axis sensors could be used to redundantly determine its y-axis coordinate. This type of position sensing arrangement may satisfy the redundancy requirements of the system, however, the use of numerous position sensors can increase the cost and complexity of the system.